Hillary Clinton is so far ahead of Donald Trump in the race for the presidency that she no longer feels the need to pay attention to him.

Buoyed by a double-digit lead in some national polls, Mrs Clinton is now looking past her Republican rival entirely, and will no longer counter allegations made by him.

"I don't even think about responding to him any more," Mrs Clinton said when asked about his charge that American media outlets are in cahoots with her presidential campaign.

"He can say whatever he wants to. He can run his campaign however he wants to, he can go off on tangents, he can go to Gettysburg and say he's gonna sue women who've made accusations against him," she added, referring to a speech given by Mr Trump the previous day. "I'm going to keep talking about what we want to do."

With only 15 days until the election, two separate polls have given Mrs Clinton a 12-point lead over Mr Trump, with the real estate mogul's support tanking among key voter groups.

An 'ABC News/Washington Post' poll released yesterday corroborated the findings of a study published earlier this week by the Monmouth University Polling Institute which showed Mrs Clinton leading Mr Trump 50pc to 38pc in a four-way contest with two minor party candidates.

Mrs Clinton's long-standing support among female voters has increased to 20 points following allegations that Mr Trump sexually harassed multiple women, according to the poll, while the study suggested the former first lady was leading for the first time among men, although the four-point advantage was within the margin of error.

But sources inside the operation have said Clinton strategists are quietly considering the possibility of a landslide victory.

In a sign of that confidence Mrs Clinton told journalists this week that her campaign was shifting its attention to trying to take back control of the Republican-majority congress, by helping Democratic politicians get elected in state races.

"We're going to be emphasising the importance of electing Democrats down the ballot," Mrs Clinton said.

The Trump campaign has remained defiant in the face of such optimism. "The fact is that this race is not over," Kellyanne Conway, Mr Trump's campaign manager, said yesterday. "He's not - we're not - giving up. We know we can win this."